The present invention relates to a new and distinct cultivar of hydrangea that is grown for use as an indoor floral potted plant and an outdoor ornamental flowering shrub. The new cultivar is known botanically as Hydrangea macrophylla and will be referred to hereinafter by the cultivar name ‘RIE 04’.
‘RIE 04’ resulted from a breeding program that was conducted by the inventor at the inventor's nursery in Kyoto, Japan and began in 1990. The purpose of the breeding program was to produce new varieties of floral potted hydrangeas that exhibit new and unique flowers and flower color.
Between May 1990 and May 1993 the inventor assembled a collection of unnamed and unreleased hybrids from a sequence of deliberate pollinations involving the following cultivars, all unpatented, and available in commerce in Japan: Hydrangea macrophylla ‘Otafuku’, Hydrangea macrophylla, ‘Yamaajisai’, and Hydrangea macrophylla ‘Fijinishiritaki’. The inventor did not record which variety was used as male parent and which as female parent. In May 1993, the inventor carried out a deliberate pollination between one unnamed plant from the inventor's collection as female parent and the variety Hydrangea macrophylla ‘Sumidanohanabi’ (unpatented) as male parent.
The pollination described above produced thirty-five individual varieties, which the inventor considered novel and unusual. One of these individual varieties was selected by the inventor in June 1994 and is the subject of the present invention, ‘RIE 04’.
‘RIE 04’ is a deciduous shrub that exhibits large medium-green leaves and yellow-green to dark pink flowers that bloom in spring and summer. Selection was based on the distinguishing characteristics of flowers, flower color, and inflorescence development. ‘Lace cap’ type hydrangeas produce showy sterile flowers along the outside of the inflorescence, and small inner flowers that are fertile flowers. When an individual inflorescence of ‘RIE 04’ first opens, it looks like a ‘lace cap’ type inflorescence with large sterile flowers on the edge. However, unlike the ‘lace cap’ type Hydrangea, the inflorescence eventually fills out completely. Within the inflorescence, center fertile flowers are intermixed with center sterile flowers, so that as the inflorescence develops further, the sterile flowers in the center open fully to then cover the smaller fertile flowers. ‘RIE 04’ is distinguishable from the parent plants by flower color, and unique inflorescence development, which produces an average of 275 sterile flowers and 150 fertile flowers per inflorescence.
The inventor considers that ‘RIE04’ is distinct from other varieties of Hydrangea unknown to the inventor in the following respects:
First, whereas other varieties of Hydrangea in commerce have four petals per floret on a flat, one-dimensional plane, ‘RIE 04’ has two to three layers of petals per floret, creating a double-flower appearance.
Second, whereas many novel varieties have been found in, or brought from, Japan in recent years, none appear to have the combination of uniqueness of flower form as above combined with greater vigor and faster growing to flowering stage which typifies ‘RIE 04’.
Third, the vigor of ‘RIE 04’ is evident in its strong thick stems which do not require staking to support the heavy blooms. ‘RIE 04’, although vigorous, exhibits a shorter internode distance than many other commercial forms of Hydrangea, allowing ‘RIE 04’ to be grown commercially with less or even no application of growth regulating chemical.
‘RIE 04’ was first asexually propagated, by the inventor in the spring of 1995 in a cultivated area of Kyoto, Japan. The method used for asexual propagation was softwood cuttings. The characteristics of the new Hydrangea cultivar named ‘RIE 04’ have been determined stable and are reproduced true to type in successive generations.